In stored energy combustors and other combustors, it is known that having a swirl stabilized flame is advantageous. For instance, this is true of a typical stored energy combustor wherein oxidant from a source is admitted to an oxidant delivery tube where it passes through a control valve on its way to a combustor in a rather precisely controlled manner. The oxidant passes through a sonic orifice which typically has a diffuser downstream so that pressure loss is minimized. From there, the oxidant is delivered to a combustor where fuel is injected for ignition with the oxidant. Downstream of the combustor, the hot gases of combustion pass through another sonic orifice into a turbine which is driven thereby.
With such an arrangement, the combustor is advantageously characterized by utilization of a swirl stabilized flame. Typical conditions just before and after ignition are such that combustion chamber pressure increases following combustion in a manner whereby the combustor pressure drop before ignition is many times higher than the combustor pressure drop after ignition. In like fashion, the air swirl velocity falls after ignition to a value only a fraction of the velocity before ignition.
Generally speaking, it is known that the combustor pressure drop before ignition must not be too great because the resulting high velocity would inhibit ignition. Similarly, the pressure drop after ignition would then be such that the resulting velocity would be very low, i.e., the velocity might possibly not be sufficient to air atomize fuel. As a result, it has generally been thought necessary to either use fuel pressure to atomize the fuel or otherwise suffer the consequences of carbon buildup.
The present invention is directed to overcoming one or more of the foregoing problems and accomplishing one or more of the resulting objectives.